It is known that the optics with X-rays are composed by a plurality of coaxial and confocal mirrors having a trunco-conical structure with a double cone, with a parabola/hyperbola having polynomial profiles or with other geometrical configurations, inserted one in the other in a manner to form a very compact group.
In view of the particular application, these mirrors must have the following principal properties among which:
a) reflecting surfaces for the geometries and the rough texture required in the optical project; PA1 b) the thickness of the walls as small as possible for the purpose of minimizing the loss of collection surfaces; PA1 c) the possibility to be produced by a process of repetition starting from mandrels having the shape of the negative of the profile required in the optics with X-rays; PA1 d) use of materials having a high module of elasticity in order to achieve low thickness, low density for the purpose of minimizing the weight, low coefficient of thermal expansion and a high coefficient of thermal conductivity for the purpose of minimizing the distortions resulting from the temperature and optimum mechanical stability during the period of time required by the process.
A mirror which satisfies all these properties is known and is described in the published application of the European Patent Office, EPA 0670576. According to this European application, a mirror having the properties listed hereinabove comprises a structural element of support or a carrier constituted by a ceramic material which is selected among silicon carbide, a carbide of silicized silicon and boron nitride; an intermediate layer of a polymerized epoxidized resin and a layer of gold. The carrier constituted by silicon carbide or by the boron nitride is obtained by the process of depositions of chemical vapors (CVD--Chemical Vapour Deposition). On the contrary, in the case of silicized silicon carbide the carrier is obtained by a sintering process. These methods used for the production of the carrier or the supporting element, even if they may be carried out in industry, are not devoid of drawbacks. These drawbacks are due mostly to the fact that these procedures are quite long and cannot be carried out easily in actual practice so that they increase substantially the cost of the finished mirror.